#include <stdio.h>

#define M 100

int main()
{
   printf("M: %d\n",M);
   printf("hello world1\n");
  // printf("hello world2\n");
   //printf("hello world3\n");
   //printf("hello world4\n");
   printf("hello world5\n");


  //条件编译
#ifdef DEBUG 
   printf("hello debug!\n");
#else
   printf("hello release\n");
#endif

}
